Added arrow key navigation to Overview Mode

ash/wm/overview/window_grid.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/wm/overview/window_grid.h"
+
+#include "ash/screen_util.h"
+#include "ash/shell.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/overview/scoped_transform_overview_window.h"
+#include "ash/wm/overview/window_selector.h"
+#include "ash/wm/overview/window_selector_item.h"
+#include "base/memory/scoped_vector.h"
+#include "third_party/skia/include/core/SkColor.h"
+#include "ui/aura/window.h"
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/vector2d.h"
+#include "ui/views/background.h"
+#include "ui/views/view.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+namespace {
+
+// An observer which holds onto the passed widget until the animation is
+// complete.
+class CleanupWidgetAfterAnimationObserver : public ui::LayerAnimationObserver {
+ public:
+  explicit CleanupWidgetAfterAnimationObserver(
+      scoped_ptr<views::Widget> widget);
+
+  // ui::LayerAnimationObserver:
+  virtual void OnLayerAnimationEnded(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationAborted(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+  virtual void OnLayerAnimationScheduled(
+      ui::LayerAnimationSequence* sequence) OVERRIDE;
+
+ private:
+  virtual ~CleanupWidgetAfterAnimationObserver();
+
+  scoped_ptr<views::Widget> widget_;
+
+  DISALLOW_COPY_AND_ASSIGN(CleanupWidgetAfterAnimationObserver);
+};
+
+CleanupWidgetAfterAnimationObserver::CleanupWidgetAfterAnimationObserver(
+    scoped_ptr<views::Widget> widget)
+    : widget_(widget.Pass()) {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->AddObserver(this);
+}
+
+CleanupWidgetAfterAnimationObserver::~CleanupWidgetAfterAnimationObserver() {
+  widget_->GetNativeWindow()->layer()->GetAnimator()->RemoveObserver(this);
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationEnded(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationAborted(
+    ui::LayerAnimationSequence* sequence) {
+  delete this;
+}
+
+void CleanupWidgetAfterAnimationObserver::OnLayerAnimationScheduled(
+    ui::LayerAnimationSequence* sequence) {
+}
+
+// A comparator for locating a given target window.
+struct WindowSelectorItemComparator
+    : public std::unary_function<WindowSelectorItem*, bool> {
+  explicit WindowSelectorItemComparator(const aura::Window* target_window)
+      : target(target_window) {
+  }
+
+  bool operator()(WindowSelectorItem* window) const {
+    return window->HasSelectableWindow(target);
+  }
+
+  const aura::Window* target;
+};
+
+// Conceptually the window overview is a table or grid of cells having this
+// fixed aspect ratio. The number of columns is determined by maximizing the
+// area of them based on the number of window_list.
+const float kCardAspectRatio = 4.0f / 3.0f;
+
+// The minimum number of cards along the major axis (i.e. horizontally on a
+// landscape orientation).
+const int kMinCardsMajor = 3;
+
+// In the conceptual overview table, the window margin is the space reserved
+// around the window within the cell. This margin does not overlap so the
+// closest distance between adjacent window_list will be twice this amount.
+const int kWindowMargin = 30;
+
+const int kOverviewSelectorTransitionMilliseconds = 100;
+
+// The color and opacity of the overview selector.
+const SkColor kWindowOverviewSelectionColor = SK_ColorBLACK;
+const unsigned char kWindowOverviewSelectorOpacity = 128;
+
+// Returns the vector for the fade in animation.
+gfx::Vector2d GetVectorFor(WindowSelector::Direction direction,

[flackr, 2014/05/29 20:04:25]

nit: The name could better explain what the method does, perhaps call it
GetSlideVectorForFadeIn?

[Nina, 2014/06/02 22:04:38]

Done.

+                           const gfx::Rect& bounds) {
+  gfx::Vector2d vector;
+  switch (direction) {
+    case WindowSelector::DOWN:
+      vector.set_y(bounds.width());
+      break;
+    case WindowSelector::RIGHT:
+      vector.set_x(bounds.height());
+      break;
+    case WindowSelector::UP:
+      vector.set_y(-bounds.width());
+      break;
+    case WindowSelector::LEFT:
+      vector.set_x(-bounds.height());
+      break;
+  }
+  return vector;
+}
+
+}  // namespace
+
+WindowGrid::WindowGrid(aura::Window* root_window,
+                       std::vector<WindowSelectorItem*> window_list)
+                         : root_window_(root_window),

[flackr, 2014/05/29 20:04:25]

nit: I believe the : should be indented 4 from the start of line.

[Nina, 2014/06/02 22:04:38]

Done.

+                           window_list_(window_list) {

[flackr, 2014/05/29 20:04:25]

I believe this will create a copy when called and another copy to assign to
local variable. The simplest approach might be to just have it build its
windowselectoritem list from the complete list of window pointers.

[Nina, 2014/06/02 22:04:38]

Done.

+  PositionWindows(true);
+}
+
+WindowGrid::~WindowGrid() {
+}
+
+WindowSelectorItem* WindowGrid::RemoveWindow(aura::Window* window) {
+  ScopedVector<WindowSelectorItem>::iterator iter =
+      std::find_if(window_list_.begin(), window_list_.end(),
+                   WindowSelectorItemComparator(window));
+  if (iter == window_list_.end())
+    return NULL;
+
+  WindowSelectorItem* removed_item = *iter;
+  removed_item->RemoveWindow(window);
+
+  // If there are still windows in this selector entry then the overview is
+  // still active and the active selection remains the same.
+  if (!removed_item->empty())
+    return NULL;

[flackr, 2014/05/29 20:04:25]

This seems like odd behavior to sometimes not return the item. I'd prefer to see
all of the removal of the WindowSelectorItem handled in WindowGrid and
WindowSelector can just check if WindowGrid is empty after removing the item.

[Nina, 2014/06/02 22:04:38]

Done.

+
+  // We need to get this value before we erase the window to prevent unspecified
+  // behavior.
+  size_t removed_index = iter - window_list_.begin();
+  window_list_.erase(iter);
+  if (!empty()) {
+    PositionWindows(true);
+
+    // If existing, reposition the selection widget.
+    if (selection_widget_) {
+      if (selected_index_ >= removed_index) {
+        if (selected_index_ != 0) {

[flackr, 2014/05/29 20:04:25]

don't nest if's for a single condition, i.e.
if (selected_index_ > 0 && selected_index >= removed_index)
  selected_index_ --;

[Nina, 2014/06/02 22:04:38]

Done.

+          selected_index_--;
+        }
+      }
+      ui::ScopedLayerAnimationSettings animation_settings(
+            selection_widget_->GetNativeWindow()->layer()->GetAnimator());
+      animation_settings.SetTransitionDuration(
+          base::TimeDelta::FromMilliseconds(
+              ScopedTransformOverviewWindow::kTransitionMilliseconds));
+      animation_settings.SetPreemptionStrategy(
+          ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+      selection_widget_->SetBounds(GetSelectionBounds());
+    }
+  }
+
+  return removed_item;
+}
+
+void WindowGrid::PositionWindows(bool animate) {
+  CHECK(!window_list_.empty());
+
+  gfx::Size window_size;
+  gfx::Rect total_bounds = ScreenUtil::ConvertRectToScreen(
+      root_window_,
+      ScreenUtil::GetDisplayWorkAreaBoundsInParent(
+          Shell::GetContainer(root_window_, kShellWindowId_DefaultContainer)));
+
+  // Find the minimum number of window_list per row that will fit all of the
+  // window_list on screen.
+  num_columns_ = std::max(
+      total_bounds.width() > total_bounds.height() ? kMinCardsMajor : 1,
+      static_cast<int>(ceil(sqrt(total_bounds.width() * window_list_.size() /
+                                 (kCardAspectRatio * total_bounds.height())))));
+  num_rows_ = ((window_list_.size() + num_columns_ - 1) / num_columns_);
+  window_size.set_width(std::min(
+      static_cast<int>(total_bounds.width() / num_columns_),
+      static_cast<int>(total_bounds.height() * kCardAspectRatio / num_rows_)));
+  window_size.set_height(window_size.width() / kCardAspectRatio);
+
+  // Calculate the X and Y offsets necessary to center the grid.
+  int x_offset = total_bounds.x() + ((window_list_.size() >= num_columns_ ? 0 :
+      (num_columns_ - window_list_.size()) * window_size.width()) +
+      (total_bounds.width() - num_columns_ * window_size.width())) / 2;
+  int y_offset = total_bounds.y() + (total_bounds.height() -
+      num_rows_ * window_size.height()) / 2;
+  for (size_t i = 0; i < window_list_.size(); ++i) {
+    gfx::Transform transform;
+    int column = i % num_columns_;
+    int row = i / num_columns_;
+    gfx::Rect target_bounds(window_size.width() * column + x_offset,
+                            window_size.height() * row + y_offset,
+                            window_size.width(),
+                            window_size.height());
+    target_bounds.Inset(kWindowMargin, kWindowMargin);
+    window_list_[i]->SetBounds(root_window_, target_bounds, animate);
+  }
+
+  // If we have less than |kMinCardsMajor| windows, adjust the column_ value to
+  // reflect how many "real" columns we have.
+  if (num_columns_ > window_list_.size())
+    num_columns_ = window_list_.size();
+}
+
+void WindowGrid::CreateSelectionWidget(WindowSelector::Direction direction) {
+  // Position the index in the "first" window relative to the chosen direction.
+  switch (direction) {
+    case WindowSelector::LEFT:
+      selected_index_ = window_list_.size() - 1;
+      break;
+    case WindowSelector::UP:
+      selected_index_ = num_rows_ * num_columns_ - 1;
+      if (selected_index_ >= window_list_.size())
+        selected_index_ -= num_columns_;
+      break;
+    case WindowSelector::RIGHT:
+    case WindowSelector::DOWN:
+      selected_index_ = 0;
+      break;
+  }
+  InitSelectionWidget(direction);
+}
+
+bool WindowGrid::Move(WindowSelector::Direction direction) {
+  DCHECK(selection_widget_);
+  bool out_of_bounds = MoveSelectedIndex(direction);
+
+  gfx::Vector2d fade_out_direction =
+      GetVectorFor(direction, selection_widget_->GetNativeWindow()->bounds());
+  // If the selection widget is already active, fade it out in the selection
+  // direction.
+  views::Widget* old_selection = selection_widget_.get();
+
+  // CleanupWidgetAfterAnimationObserver will delete itself (and the
+  // widget) when the animation is complete.
+  {
+    new CleanupWidgetAfterAnimationObserver(selection_widget_.Pass());
+    ui::ScopedLayerAnimationSettings animation_settings(
+        old_selection->GetNativeWindow()->layer()->GetAnimator());
+    animation_settings.SetTransitionDuration(
+        base::TimeDelta::FromMilliseconds(
+            kOverviewSelectorTransitionMilliseconds));
+    animation_settings.SetPreemptionStrategy(
+        ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+    old_selection->SetOpacity(0);
+    old_selection->GetNativeWindow()->SetBounds(
+        old_selection->GetNativeWindow()->bounds() + fade_out_direction);
+    old_selection->Hide();
+  }
+  if (!out_of_bounds) {
+    // The newly selected window is in this grid, animate a new selection
+    // widget.
+    InitSelectionWidget(direction);

[flackr, 2014/05/29 20:04:25]

It looks like you're always destroying the old selection widget and creating a
new one? You shouldn't have to do this if the selection is changing on the same
root.

[Nina, 2014/06/02 22:04:38]

Well actually when you are leaving the boundaries of the grid but you are still
in the same root, we do need to recreate the selection widget (think on the
widget fading out in a row and in in another). Adding logic to decide if we
recreate the widget or not would involve having an "out" parameter in
MoveSelectedIndex(). I think this is a bit of an overkill. WDYT?

[flackr, 2014/06/03 17:12:07]

I think this is necessary. The animations of the two windows will not be
perfectly in sync and we don't want the double box effect that is currently
happening.

[Nina, 2014/06/04 20:21:13]

OK, done!

+  } else {
+    // The selection is out of the bounds of this grid, kill the selection
+    // widget.
+    selection_widget_.reset();

[flackr, 2014/05/29 20:04:25]

You've already passed off the selection_widget_ pointer on line 260, currently
it should already be NULL.

[Nina, 2014/06/02 22:04:38]

Yep. Removed.

+  }
+  return out_of_bounds;
+}
+
+WindowSelectorItem* WindowGrid::SelectedWindow() const {
+  CHECK(selected_index_ < window_list_.size());
+  return window_list_[selected_index_];
+}
+
+void WindowGrid::InitSelectionWidget(WindowSelector::Direction direction) {
+  selection_widget_.reset(new views::Widget);
+  views::Widget::InitParams params;
+  params.type = views::Widget::InitParams::TYPE_POPUP;
+  params.keep_on_top = false;
+  params.ownership = views::Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
+  params.opacity = views::Widget::InitParams::TRANSLUCENT_WINDOW;
+  params.parent = Shell::GetContainer(root_window_,
+                                      kShellWindowId_DefaultContainer);
+  params.accept_events = false;
+  selection_widget_->set_focus_on_creation(false);
+  selection_widget_->Init(params);
+  views::View* content_view = new views::View;
+  content_view->set_background(
+      views::Background::CreateSolidBackground(kWindowOverviewSelectionColor));
+  selection_widget_->SetContentsView(content_view);
+  selection_widget_->GetNativeWindow()->parent()->StackChildAtBottom(
+      selection_widget_->GetNativeWindow());
+
+  const gfx::Rect target_bounds = GetSelectionBounds();
+  gfx::Vector2d fade_out_direction =
+          GetVectorFor(direction, target_bounds);
+  gfx::Display dst_display = gfx::Screen::GetScreenFor(root_window_)->
+      GetDisplayMatching(target_bounds);
+
+  selection_widget_->Show();
+  // New selection widget starts with 0 opacity and fades in.
+  selection_widget_->GetNativeWindow()->layer()->SetOpacity(0);
+  selection_widget_->GetNativeWindow()->SetBoundsInScreen(
+      target_bounds - fade_out_direction, dst_display);
+  ui::ScopedLayerAnimationSettings animation_settings(
+      selection_widget_->GetNativeWindow()->layer()->GetAnimator());
+  animation_settings.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
+      kOverviewSelectorTransitionMilliseconds));
+  animation_settings.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  selection_widget_->SetBounds(target_bounds);
+  selection_widget_->SetOpacity(kWindowOverviewSelectorOpacity);
+
+  // Send an a11y alert so that if ChromeVox is enabled, the item label is read.
+  SelectedWindow()->window_label()->GetContentsView()->
+      NotifyAccessibilityEvent(ui::AX_EVENT_FOCUS, true);

[flackr, 2014/05/29 20:04:25]

Perhaps we could even focus the current window selector item, assuming it
extends custombutton, rather than having a custombutton.

[Nina, 2014/06/02 22:04:38]

I changed it so that it focuses the transparent button. How do you think it
looks?

[flackr, 2014/06/03 17:12:07]

Looks better! It's not actually focused but pretending to be as far as I can
tell. I think the alert should be delivered from Move though after we've
determined the new selected window.

[Nina, 2014/06/04 20:21:13]

Yeah, we are artificially sending a "Focus" event to the a11y framework. Moved.

+}
+
+bool WindowGrid::MoveSelectedIndex(WindowSelector::Direction direction) {
+  bool out_of_bounds = false;
+  switch (direction) {
+    case WindowSelector::RIGHT:
+      if (selected_index_ >= window_list_.size() - 1)
+        out_of_bounds = true;

[flackr, 2014/05/29 20:04:25]

Use early returns. It also feels strange that this leaves selected_index_ in a
semi-random state.

[Nina, 2014/06/02 22:04:38]

Done.
Yeah, but on the other hand returning true means that in the next call the index
is going to be reset.

+      else
+        selected_index_++;
+      break;
+    case WindowSelector::LEFT:
+      if (selected_index_ == 0)
+        out_of_bounds = true;
+      else
+        selected_index_--;
+      break;
+    case WindowSelector::DOWN:
+      if (selected_index_ + num_columns_ >= window_list_.size())
+        selected_index_ = (selected_index_ + 1) % num_columns_;
+      else
+        selected_index_ += num_columns_;
+      if (selected_index_ == 0 || selected_index_ >= window_list_.size())
+        out_of_bounds = true;
+      break;
+    case WindowSelector::UP:
+      if (selected_index_ == 0) {
+        out_of_bounds = true;
+      } else {
+        if (selected_index_ < num_columns_) {
+          selected_index_--;

[flackr, 2014/05/29 20:04:25]

This seems odd, up is the same as left on the top column? I'd expect it to
always go up a row even if that meant changing displays.

[Nina, 2014/06/02 22:04:38]

Please see the new docs on the header file that explain how movement works.

+          if (!(selected_index_ + num_columns_ >= window_list_.size())) {
+            selected_index_ += num_columns_ * (num_rows_ - 1);
+            if (selected_index_ >= window_list_.size())
+              selected_index_ -= num_columns_;
+          }
+        } else {
+          selected_index_ -= num_columns_;
+        }
+      }
+      break;
+    }
+  return out_of_bounds;
+}
+
+const gfx::Rect WindowGrid::GetSelectionBounds() const {
+  gfx::Rect bounds = SelectedWindow()->target_bounds();
+  bounds.Inset(-kWindowMargin, -kWindowMargin);
+  return bounds;
+}
+
+}  // namespace ash